Telephone-transmitter.



Patented my 23, wol.

J. e. Nouan.

TELEPHONE TRANSMITTER.

(Applxcatmn Blad Apr 11, 1901 1|u||l|lllimmllml-ilmnnf.Iz',v

(No Model.)

'UNITED' STATES PATENT OFFICE.

JAMES Cr. NOLEN, OF CHICAGO, ILLINOIS.

TELEPHONE-TRANSMITTER.'

SPECIFICATION forming part of Letters Patent No. 678,972, dated July 23,1901.

Application filed April 11, 1901. Serial No. 55,33 5. (No model.)

To all whom t may concern:

Be it known that I, JAMES G. NoLEN, a citizen of the United States,residing at Chicago, county of Cook, and State of Illinois," haveinvented certain new and useful Improvements in Telephone-Transmitters;and I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable personsskilled in theart to which it appertains to make and use the same.

One object of my invention is to provide a telephone-transmitter whichis very sensitive, efficient, and durable in operation and in which theresisting medium, comprising the iinely-divided carbon, is held in astate of stress, by means of which a practically constant normalresistance is provided and by which the normal resistance may be quicklyand easily varied by a slight turn of a nut, attended with very littlefriction when the instrument is in operation.

A further object of my invention is to provide a means by which a stressis placed upon the diaphragm, so as to render it extremely sensitive andresponsive to the voice-Waves that impinge against it at the time whenconversation is being transmitted by its operation.

In the drawings, Figure 1 is a view of the back of the instrument. Fig.2 is a section through lines 2 2 of Fig. 1. Fig. 3 represents thediaphragm and the cup for containing the finely-divided resistancemedium.

In all of the drawings the same letters of reference indicate similarparts.

A is an eXteriorly-threaded ring. A is a ring of slightly smallerdiameter, adapted to hold the diaphragm in place on said threaded ringin contact with the outer circumferential edges thereof.

Screws a12 and als are adapted to be placed through perforations in theyoke-piece A2 and to hold the said yoke in fixed relation with saidring.

a, is a cup for containing the finely-divided material which composesthe resisting medium of the transmitter. This cup I prefer to make ofglass and cast the threads around the outside thereof and theperforations in the bottom at the time the glass ismolded.

a2 is a stem connected to the electrode o3.

This electrode, in the form of a plunger or disk, is preferably composedpartially of carbon, or it may be made of some non-oxidizable metaliixed to the stem a2, or it may be an integral part of the said stem.

a3 is a carbon-electrode disk adapted to iit against the rear interiorwall of the cap a'. This cap is preferably'made of brass and is adaptedto be screwed over the cup or case a.

a5 is a curved sheetmetal four armed spring adapted to be placed on theinside of the cup or case a and to exert a pressure against theplunger-electrode a3, tending to force the case on the stem a2. Asimilar spring a is adapted to be placed around the stem a2 on theoutside of the case a and to draw the oase a in the opposite directionto `that exerted by the spring a?, so that the case a and diaphragm aswill by the opposing tension of both springs be held in a state ofdelicate equilibrium. This condition may be adjusted by varying therelative strength of the springs.

all is a nut adapted to be screwedover the end of the stem o2 when theparts are assembled.

a8 is the ordinary diaphragm of a telephone-transmitter, adapted to beattached to the cap a by means of the soreT a7.

a9 is an interiorly-threaded bushing, into which the stem o? of theplunger 0,3 is adapted to project. d10 is a screw to fasten and hold thestem a2 in position in the said bushing.

an is an insulated bushing for insulating a9 from the bridge A2.

et is a thread cut on the outside circumfere ence of the ring A for thepurpose of attaching the ordinary mouthpiece and cap to this mytelephone-transmitter unit.

L15 and am are the electrical terminals of the instrument.

When the instrument is assembled, as shown in Fig. 2, the tension of thesprings a5 and et may be regulated by tightening or loosening the nut eton the stem o2, and by this means the case and diaphragm will be held ina state of delicate equilibrium. By tightening the nut a and increasingthe tension upon the spring a6 the diaphragm a8 may be shoved outwardlyand elastically held or maintained under a tension, which renders theinstrument exceedingly delicate and IOO sensitive to the effect of thevoice-waves that impinge against the diaphragm as. It will b e noticedthat the diaphragm carries the cap a and the cup or case a and all thatnis c ontained therein, with the exception of the stationary plunger 0.3and the stem a?. Therefore the granulated inely-divided resistingmaterial which is contained between the plunger a3 and the electrode a4of the cap a is bodily moved and vibrated when the diaphragm is set inmotion.

My instrument is susceptible of two adjustments, which may be made afterit has been assembled ready for operation. First, by moving thev stem a2in the bushing a9 and by tightening set-screw am; second, by moving thenut a along the stem a2 to compress the springs a5 and 0.5. Both oreither of these adjustments may be made to effect the stress orcondition of the diaphragm t8 and the condition of the granular mediumbetween the said electrodes.

The result of the construction just described is to produce aninstrument of an extraordinary sensitive nature and one that may becheaply constructed, quickly assembled, adjusted to the most minutevariations, and very durable in its operation. The double spring, forthe purpose described, in conjunction with the diaphragm as, rendersthis instrument a very durable, yet an exceedingly sensitive andresponsive apparatus. These springs may be unequally powerful.

I have shown sheet-metal springs having four arms each; but it isevident that helil cally-coiled wire springs may be used in lieu of thisform of'spring without departing from the spirit and gist of myinvention.

The mode of operation will be apparent from the foregoing descriptionand drawings to those skilled in the art.

Having described my invention, what I claim as useful, anddesire tosecure' by Letters Patent of the United States, is.-

1. A telephone-transmitter comprising a diaphragm, a case carried bysaid diaphragm, an electrode in Vsaid case adapted to move therewith, anopposing, fixed electrode in said case, carried upon a stem passingthrough a perforation in said case, a resistance-varying materialbetween said electrodes, and springs adapted to exert a pressure to movethe case in opposite directions, substantially as set forth.

2. A telephone -transmitter comprising a diaphragm, a case carried bysaid diaphragm, an electrode in said case adapted to move therewith, anopposing, fixed electrode in said case, a resistance-varying materialbetween said e1ectrodes,counteracting-sprin gs adapted to exert apressure to move the case in opposite directions, and a means foradjusting said springs, substantially as set forth.

3. A telephone -transmitter comprising a diaphragm, a case carried bysaid diaphragm, an electrode in said case adapted to move therewith,anopposing, fixed electrode, in said case, carried upon a stempassingthrough a perforation in said case, a resistance-varying materialbetween said electrodes, a spring between the fixed electrode and therear wall of said case, a nut on the stem carrying the fixedelectrode,and a counteractin g-sprin g between said nut and saidcase,substantially as set forth.

In testimony whereof I have signed this specification, in the presenceof two susbcribing Witnesses,this 27th dayof February, A. D. 1901.

JAMES G. NOLEN.

Witnesses FORE BAiN, M. F. ALLEN.

